How to get the keys from array

Question

I am using GCM(Google could messaging) for the very first time and i am stuck with some problem. Although the problem has nothing to do with the GCM.I have a JSON data

$data='{"multicast_id":7917175795873320166,"success":6,"failure":0,"canonical_ids":4,

"results":[

{"registration_id":"3","message_id":"m1"},
{"message_id":"m1"},
{"message_id":"m1"},
{"registration_id":"3","message_id":"m1"},

{"registration_id":"3","message_id":"m1"},

{"registration_id":"3","message_id":"m1"}]}';

$newData=json_decode($data);

Now what i want is the keys in the result array for which registration_id is set but i am unable to do so. I can access the registration_Id like $newData->results[0]->registration_id

I have found that array_keys() returns the keys in an array but how can i get the keys in the $newData->results array for which $newData->results[$index]->registration_id is set? The major issue is that i cant use the foreach loop for doing it. Hope i will get some help here.

Because i can do it easily with a foreach loop. But i wan to know if i can achieve it with any inbuilt function also. — Let me see
– Let me see, Commented Jan 13, 2014 at 13:26

Community · Accepted Answer · 2023-11-20 22:45:59Z

1

Sure. First off, use the second param of json_decode so you're actually working with an array and not an object. Then filter the array with the items you want (where registration_id is set) and get the keys.

$newData=json_decode($data, true);

$filteredResults = array_filter($newData['results'], function($item) {
    return isset($item['registration_id']);
});

print_r(array_keys($filteredResults));

Working example: http://3v4l.org/e8doL

Note this code assumes you are using PHP 5.3 or later. If you are on an earlier version, you'll need to define your array_filter callback function first and pass it in rather than using an anonymous function.

edited Nov 20, 2023 at 22:45

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answered Jan 13, 2014 at 13:27

jszobody

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3 Comments

Let me see Over a year ago

Thanks for the answer. i was unaware of the bo0lean parameter in json_decode(). Thanks for letting me know about it.

jszobody Over a year ago

@Letmesee Sure thing. So does this provide what you were looking for?

Let me see Over a year ago

Yes absolutely. I will mark it as an answer as soon as i will be be able to do so. Thanks again

Steven Schmutz · Accepted Answer · 2014-01-13 13:30:51Z

1

The reason that you can only address the items in object mode, is due to the way the json_decode was called.

To return $data as an associative array, use:

$newData=json_decode($data, true)

answered Jan 13, 2014 at 13:30

Steven Schmutz

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1 Comment

Amal Over a year ago

This doesn't address the original question: how can i get the keys in the $newData->results array for which $newData->results[$index]->registration_id is set? .

Community · Accepted Answer · 2023-11-17 19:53:52Z

1

$newData=json_decode($data, true)

if you're passing the second param true then it converts the json to assosiative array(an array with key val pair).Official doc Here is official documentation Json_decode Php Official

an example to show that

<?php
$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

var_dump(json_decode($json));
var_dump(json_decode($json, true));

?>

its output will be

object(stdClass)#1 (5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}

array(5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}

edited Nov 17, 2023 at 19:53

CommunityBot

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answered Jan 13, 2014 at 13:35

Kaushik

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